1. Field of the Invention
The present invention relates to arrangements for releasably coupling an engine to a driven device, so that the driven device need not have an engine permanently attached thereto and so that the engine may be used with other driven devices.
2. History of the Prior Art
There are many driven devices such as tools that are advantageously powered such as by a gasoline engine. Examples of such driven devices include weed eaters, hedge trimmers, blowers, pumps, drills, chain saws, circular saws, electrical generators, winches, posthole diggers, lawn edgers, lawn mowers, air compressors, outboard motors and wheeled vehicles such as go-carts and mopeds. Such devices are typically power driven by attaching a gasoline engine thereto so that the engine becomes a permanent part of the device. This is wasteful in that the engine may thereafter be used only with that particular tool or driven device and cannot be used with other devices. Aside from the obvious increase in cost of the driven device because of the necessary inclusion of an engine therewith, other disadvantages include the increased weight and size of the device because of the permanent presence of the engine. Thus, storage of such devices is made more difficult because of the increased storage space required by the separate gasoline engine permanently coupled to each such device.
Therefore, it would be advantageous to provide an arrangement which enables the releasable coupling of a driven device to a source of power such as a gasoline engine. In this manner, the engine could be coupled to the driven device when it is desired to use such driven device, then uncoupled from the driven device in preparation for the use of the engine with other driven devices. This would enable a single engine to be used with a variety of different power tools and other driven devices. Thus, it would be possible for a single engine to be used with various different power tools in a home workshop, for example, then taken outside and used with each of a plurality of different garden tools.
Various different types of coupling arrangements are known. Examples of certain existing coupling arrangements include U.S. Pat. No. 2,160,354 of Evans which relates to a flexible hose coupling that employs two rings in combination with lugs and mating apertures of varying width. Another example is provided by U.S. Pat. No. 904,200 of Harris which shows two sections of metal culvert joined together by a pair of rings, one of which has apertures of varying width therein and the other which has lugs mounted thereon. A further example is provided by U.S. Pat. No. 622,313 of Woodvine which relates to a standpipe coupling in which lugs on one ring mate with apertures of varying width on another ring. The surfaces adjacent the apertures are ramped to provide an increasingly tighter fit as the rings rotate relative to one another. Still further examples of conventional coupling arrangements are provided by U.S. Pat. Nos. 1,148,824 of Boje, Jr.; 2,819,028 of Brezosky et al; and 2,416,964 of Stull.
The various coupling arrangements described in the above-noted patents do not relate to the releasable coupling of an engine to a driven device and do not address the particular problems involved in such an arrangement. Thus, an arrangement for releasably coupling an engine to a driven device such as a power tool must be designed so as to rotatably couple the drive shaft of the engine to a driven shaft of the driven device. The releasable coupling arrangement must be strong, sturdy and capable of withstanding considerable force and stress, and yet at the same time must lend itself to quick coupling and uncoupling with relatively simple and limited motions that can be accomplished by hand and without the need for any tools.
In an arrangement for releasably coupling an engine to a power tool or other driven device, it is furthermore desirable that the engine be capable of manual control from the driven device itself. Thus, a manually operated engine speed control included within the driven device must be readily and releasably coupled to the engine when the engine is coupled to the driven device. The ability to control the speed of the engine from the driven device is advantageous, particularly where the driven device is relatively large and the engine itself is not located for convenient access by the operator of the driven device.
It would furthermore be desirable in cases where an engine is releasably coupled to a driven device to provide for automatic shut-off of the engine in the event that the driven device begins to uncouple from the engine, as well as to provide for quick engine shut-off from the driven device. This is a safety feature in that safety problems can arise if the engine starts to uncouple from the driven device while the driven device is being used. Also, the ability to quickly shut the engine off using a control located at the driven device is an advantageous safety feature.